liMN cells

[stevoman]

Sorry if this has already been covered, but I've been trying to track down an idiots guide to the benefits and disadvantages of LiMN vs straight lithium batteries. All the stuff I've found is written in language incompatible with my small brain.

It seems the LiMN safer chemistry cells have significantly lower capacity, but can discharge safely at higher rates, and are safer in series. Does this mean that there's little benefit for use in single cell LED applications?

I'm trying to choose some 18650s for single cell LED thrower lamps (RQ/Spear clone, DX WF-600), and trying to choose between AW 18650 and the IMR versions.

By my understanding, the standard version would have better performance for this application, am I right, or just confused?

 

[mdocod]

For most LED lights you'll be best off sticking with protected LiCo cells as there isn't much if anything to gain by going with IMR (LiMn) cells.

Before I say more, have you read through some of the "threads of interest" in this batteries/electronics part of the forum?

 

[stevoman]

I thought I'd read the relevant ones (shootout and LiIon categories), but I suspect I may be missing the basic understanding to get the information out of them.

The summary I posted above is the understanding I have got from them, but I was concerned that it wasn't accurate or complete.

It seems that in spite of not understanding, I may have come to the right conclusion anyway (not to use IMR for this application).

Thanks for your help

 

[mdocod]

The LiMn cells in RCR123 have a lot more useful application coverage as their are many small lights being produced that draw over an amp, that really push the limits of standard LiCo RCR123 cells. In the 18650 size, the LiMn cell doesn't start to have much advantage until you are moving more than ~3 amps, most flashlights don't break this barrier so the regular protected cell with more available capacity is the winner.

At the end of the day though, you have to make the decision, and there are tradeoffs and an argument for going either way. The unprotected LiMn cell, has less failure potential (no PCB to fail), and is considered safer in *most* respects. However, the protected LiCo cell can be advantageous especially in regulated LED lights that can potentially over-discharge li-ion cells long before any noticeable dimming would occur.

-Eric